The invention relates to a device for eliminating deposits in ventilation ducts by the use of cleaning fluid sprayed at high pressure.
Ventilation systems consist, on the one hand, of assemblies, such as filters, heat exchangers, air heaters or air coolers, fans and regulating members, and, on the other hand, of a ventilation-duct network. The assemblies are generally accessible from outside, so that their cleaning presents relatively few problems. External ventilation gratings and the immediate outlets and inlets of ventilation ducts are also cleaned satisfactorily in the customary way.
The cyclically necessary complete cleaning of the frequently branched and wide-ranging ventilation-duct networks presents appreciably greater problems. Depending on the ambient conditions, mixtures of particles of dirt, of grease, of metal and of dust and of chemical particles, etc. are deposited in the ventilation ducts and in time form relatively thick deposited layers. Micro-organisms, viruses, bacteria, pollen, spores, skin scales, hairs, textile fibres, paper fluff, etc. can also be included in these. The deposited layers adhere, sometimes extremely tenaciously, to the inner walls, lead to petrifactions and successively narrow the ventilation-duct cross-section. The cross-sectional narrowing results in decreasing effectiveness of the ventilation system. The more dirt is lodged in the duets, the poorer the ratio between the energy consumption and the degree of efficiency of the system becomes. Combustible deposits constitute a considerable safety risk. The deposited layers can often ignite easily and, if combustion occurs, the fire can spread throughout the duct network in the entire building. The impurities also result in a high safety risk for the persons in the vicinity of the system by virtue of the propagation of pathogenic agents.
Depending on local circumstances, pipe brushes or other special brushes, by means of which the deposits can be scraped off from the inner walls of the ventilation ducts, have hitherto been employed for the cleaning of ventilation ducts. This working method is suitable only for fat-free non-greasy deposits. Furthermore, brushing off is particularly laborious in the case of larger duct cross-sections, where the brush contour no longer corresponds to the duct cross-section, but the brush is much smaller. Moreover, fine cleaning is not achieved merely by brushing; the cleaning of longer horizontal segments, bends and branches also presents some difficulties.
Where oily or fatty deposits are concerned, flushing with hot water, to which specific solvents can be added, is carried out. Tenacious deposits are dissolved only inadequately in this way and, furthermore, a very high water consumption occurs. For cleaning at duct inlets and outlets, particularly on vapour extraction hoods and fat filters, water-cleaning guns working at high pressure are also employed, but their range is limited.
The cleaning methods and devices known thus far can therefore all not be considered as the best possible. There would have to be mentioned as disadvantages, these occurring alternately or in combination: the cleaning work has to be carried out essentially manually, a high energy and water consumption, insufficient degree of cleaning, particularly at locations in the duct network to which access is difficult from outside, an expenditure of work time which incurs high costs.